# std::filesystem::hard_link_count

From cppreference.com
< cpp‎ | filesystem

Defined in header `<filesystem>` |  |
std::uintmax_t hard_link_count( const std::filesystem::path& p ); | (1) | (since C++17)
std::uintmax_t hard_link_count( const std::filesystem::path& p, std::error_code& ec ) noexcept; | (2) | (since C++17)

Returns the number of hard links for the filesystem object identified by path p.

The non-throwing overload returns static_cast<uintmax_t>(-1) on errors.

### Parameters

p | - | path to examine
ec | - | out-parameter for error reporting in the non-throwing overload

### Return value

The number of hard links for p.

### Exceptions

Any overload not marked `noexcept` may throw std::bad_alloc if memory allocation fails.

1) Throws std::filesystem::filesystem_error on underlying OS API errors, constructed with p as the first path argument and the OS error code as the error code argument.
2) Sets a std::error_code& parameter to the OS API error code if an OS API call fails, and executes ec.`clear`() if no errors occur.

### Example

Run this code

    #include <filesystem>
    #include <iostream>
    namespace fs = std::filesystem;

    int main()
    {
        // On a POSIX-style filesystem, each directory has at least 2 hard links:
        // itself and the special member pathname "."
        fs::path p = fs::current_path();
        std::cout << "Number of hard links for current path is "
                  << fs::hard_link_count(p) << '\n';

        // Each ".." is a hard link to the parent directory, so the total number
        // of hard links for any directory is 2 plus number of direct subdirectories
        p = fs::current_path() / ".."; // Each dot-dot is a hard link to parent
        std::cout << "Number of hard links for .. is "
                  << fs::hard_link_count(p) << '\n';
    }

Possible output:

    Number of hard links for current path is 2
    Number of hard links for .. is 3

### See also

create_hard_link (C++17) | creates a hard link (function)
hard_link_count | returns the number of hard links referring to the file to which the directory entry refers (public member function of `std::filesystem::directory_entry`)

Retrieved from "https://en.cppreference.com/mwiki/index.php?title=cpp/filesystem/hard_link_count&oldid=158003"